-How Spring Web Flow fits into Spring's layered, a-la-carte "Web Stack" is illustrated below:
+How Spring Web Flow fits into Spring's layered, a-la-carte "Web Stack" is illustrated below:
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diff --git a/spring-webflow-samples/getting-started-with-spring-webflow/src/main/webapp/WEB-INF/tutorial/webflowSetup.jsp b/spring-webflow-samples/getting-started-with-spring-webflow/src/main/webapp/WEB-INF/tutorial/webflowSetup.jsp index 7949929a..b72d8d28 100644 --- a/spring-webflow-samples/getting-started-with-spring-webflow/src/main/webapp/WEB-INF/tutorial/webflowSetup.jsp +++ b/spring-webflow-samples/getting-started-with-spring-webflow/src/main/webapp/WEB-INF/tutorial/webflowSetup.jsp @@ -49,13 +49,14 @@ Inside /WEB-INF/spring, we generally recommend defining a configuration file for your application logic, and separate configuration files for framework infrastructure. For example:
-+/webapp /WEB-INF /spring app-config.xml mvc-config.xml - webflow-config.xml + webflow-config.xml + web.xmlThe example above shows the configuration for a Spring web application spread across three files. @@ -63,13 +64,24 @@ mvc-config.xml configures the Spring MVC framework infrastructure, including the properties of the DispatcherServlet. webflow-config configures the Spring Web Flow infrastructure, which plugs into Spring MVC.
++ We also generally recommend using annotations to configure your application components, and externalized XML to configure infrastructure. + This is illustrated in app-config.xml by use of the component-scan directive to scan your classpath for application components to deploy: +
++ <!-- Scans within the base package of the application for @Components to configure as beans --> + <context:component-scan base-package="org.springframework.webflow.samples.gettingstarted" /> +++ With this technique, your Spring configuration is setup once and you generally never have to update your configuration files again as new components are added to your application. +
How do I plug-in Spring Web Flow?
In webflow-config.xml, first define a flow-registry to register the flows you have defined in your application:
-+<!-- Registers the web flows that can be executed --> <webflow:flow-registry id="flowRegistry" base-path="/WEB-INF/"> <webflow:flow-location-pattern value="**/*-flow.xml" /> @@ -81,14 +93,14 @@Then, define a flow-executor that uses this registry to execute your flows:
-+<!-- Configures the engine that executes web flows in this application --> <webflow:flow-executor id="flowExecutor" flow-registry="flowRegistry" />Finally, in mvc-config.xml plug in adapters to hook the flow-executor into the Spring MVC DispatcherServlet request processing pipeline:
-+<!-- Maps requests to flows in the flowRegistry --> <bean id="flowMappings" class="org.springframework.webflow.mvc.servlet.FlowHandlerMapping"> <property name="order" value="0" /> @@ -103,9 +115,66 @@We also recommend you turn on development mode while developing so you never have to redeploy your application to test changes:
-+<webflow:flow-builder-services id="flowBuilderServices" development="true" />++ How do Spring MVC @Controllers and Web Flows co-exist in the same application? +
++ A typical Spring web application consists of a mix of stateless MVC @Controllers and stateful web flows, which are two distinct types of handlers. + When a web request comes in for a resource, the DispatcherServlet figures out which handler should be invoked. + This is done by consulting an ordered chain of HandlerMapping objects configured in your mvc-config.xml. + Generally, the first HandlerMapping consulted is the FlowHandlerMapping, which determines if the requested resource should be handled by a web flow. + If no flow handler is found, the next HandlerMapping in the chain is queried. + This is generally the DefaultAnnotationHandlerMapping, which consults explicit @RequestMapping rules defined inside annotated Spring MVC @Controllers. +
++ Setting up the HandlerMapping chain is a one-time configuration step, and makes it easy to plug in different types of handlers and mapping strategies. + A typical HandlerMapping chain for Spring web applications looks like: +
++ <!-- Maps requests to flows in the flowRegistry; for example, a request for resource /hotels/booking maps to a flow with id "hotels/booking" + If no flow is found with that id, Spring MVC proceeds to the next HandlerMapping (order=1 below). --> + <bean id="flowMappings" class="org.springframework.webflow.mvc.servlet.FlowHandlerMapping"> + <property name="order" value="0" /> + <property name="flowRegistry" ref="flowRegistry" /> + </bean> + + <!-- Maps requests to @Controllers based on @RequestMapping("path") annotation values + If no annotation-based path mapping is found, Spring MVC proceeds to the next HandlerMapping (order=2 below). --> + <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"> + <property name="order" value="1" /> + </bean> + + <!-- Maps requests to @Controllers based on controller class name convention; e.g. a request for /hotels or a /hotels sub-resource maps to HotelsController + If no class mapping is found, Spring MVC sends a 404 response and logs a pageNotFound warning. --> + <bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"> + <property name="order" value="2" /> + </bean> +++ Once a request has been mapped to a handler object such as a @Controller of web flow, the DispatcherServlet uses the HandlerAdapter registered for that kind of handler to invoke it. + This decouples the DispatcherServlet from specific handler implementations, which allows Spring MVC to support different controller technologies in an extensible manner. + As a one-time configuration step, a typical Spring web application registers HandlerAdapters that know how to invoke @Controllers and web flows when they are mapped: +
++ <!-- Enables annotated @Controllers; responsible for invoking an annotated POJO @Controller when one is mapped. --> + <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /> + + <!-- Enables web flows; responsible for calling the Spring Web Flow system to execute a flow when one is mapped. --> + <bean class="org.springframework.webflow.mvc.servlet.FlowHandlerAdapter"> + <property name="flowExecutor" ref="flowExecutor" /> + </bean> +++ To illustrate the DispatcherServlet pipeline, the following graphic illustrates the sequence when a request is mapped to a web flow:
+
++
+ The following graphic shows the sequence when a request is mapped to a @Controller:
++